Factors related to inappropriate edoxaban use

WHAT IS KNOWN AND OBJECTIVE: The aim of this study was to evaluate the appropriateness and clinical outcomes of edoxaban use, and to determine the role of clinical pharmacists in improving the efficacy and safety of edoxaban use. METHODS: A retrospective study was performed by using an electronic medical record and anticoagulation clinical data from 600 patients who received edoxaban from 1 March 2016 to 16 July 2017 at a tertiary teaching university hospital. The appropriateness of edoxaban use was assessed using eight criteria based on drug use evaluation criteria developed by the American Society of Health-System Pharmacists drug use evaluation guidelines, details in Korea Food and Drug Administration approval of edoxaban. Clinical outcomes were evaluated between the appropriately prescribed and inappropriately prescribed groups regarding the incidence of thrombosis and bleeding episodes. RESULTS AND DISCUSSION: After excluding 86 patients due to the inability to assess renal function, 514 were eligible. Appropriate use was found in 294 patients (57.2%). The most frequent inappropriate use of edoxaban was dose adjustment (60.8%) in accordance with the dosing recommendation in patients with renal insufficiency (creatinine clearance [CrCl] of 15-50 mL/min) and a low body weight of <60 kg. Moreover, there were three cases of edoxaban use in patients with prosthetic heart valves and moderate-to-severe mitral stenosis, and 15 cases of non-valvular atrial fibrillation in patients with CrCl >95 mL/min in whom edoxaban use is not recommended. Furthermore, we found that the factors related to the appropriateness of edoxaban use were <60 kg body weight (adjusted odds ratio [OR]: 0.310; confidence interval [CI]: 0.197-0.488) and CrCl <50 mL/min (adjusted OR: 0.629; CI: 0.404-0.980). There were 45 events (8.75%) of any bleeding, 9 (1.8%) of stroke/transient ischaemic attack (TIA) and four events (0.8%) of deep vein thrombosis (DVT)/pulmonary embolism (PE). However, there was no difference between the appropriately prescribed group (294 patients) and inappropriately prescribed group (220 patients) in the incidence of bleeding events (27 [9.2%] vs 18 [8.2%]), stroke/TIA (7 [2.4%] vs 2 [0.9%]) and DVT/PE (2 [0.7%] vs 2 [0.9%]), respectively. WHAT IS NEW AND CONCLUSION: Although edoxaban has a broad therapeutic window that does not require routine monitoring, it should be cautiously used in patients with renal insufficiency (CrCl <50 mL/min) and body weight <60 kg.